My last PC build was greatly influenced by what I read on this forum, indeed very useful information can be found here. Back thenI assembled AMD based machine on Athlon and Gigabyte GA-MA74 board which has been serving me very well, but now the time has come to upgrade.

I'm considering to build new machine on either intel DH77EB or Asus P8H77-M. I lean more towards intel due to its network chip versusrealtek on ASUS board, but the latter has PCI slot which is also nice for legacy stuff (like promise board for ATA133, if needed).

There is also another factor that plays role: possibility to undervolt. In this area, even after googling for weeks, I'm totally confused.

Please correct/confirm if the following is true:

1) any ivy/sandy bridge processor can be underclocked, as long as BIOS allows. Does it depend on chipset used? Can I underclock with the above boards?2) any ivy/sandy processor can be undervolted, as long as BIOS allows. Or does it also depend on chipset/CPU?

I'm still quite undecided about the CPU. Been considering i3-2120T or i5-3550. In both situations, my goal is to make as energy efficientmachine as possible. So if I go for i5-3550, I need to be sure that I can undervolt/underclock.

BTW, should I expect any difference in terms of power consumption between these two boards?

With current generations of intel CPUs it no longer makes sense to underclock or underolt. They all run about 4 watts at idle.

If you goal is to reduce total system wattage, the game is to use the most efficient motherboard. Intel's design prioritizes when they design motherboards appear to be reduced wattage. In any event, Intel motherboards tend to be the most efficient board around (though they have other drawbacks). If low wattage utilization is what you want, skip the underclock and underolt and just stick to Intel motherboards.

thanks! indeed, I have seen in many tests that all CPUs idle at approximately the same level. However, picture changes drastically under load. That's why I thought of undervolting in case I was going for picoPSU (just to be sure that I will not burn the power brick).

my goal is to make as energy efficient machine as possible. So if I go for i5-3550, I need to be sure that I can undervolt/underclock.

Underclocking and undervolting are not the same thing. You can almost always underclock.Undervolting is not supported. Moderate undervolting has typically worked well for many years with Intel CPUs thanks to their technical dominance of the market but there's no stability guarantee. Many boards do not support undervolting (or not through the BIOS anyway).Note that at the same clock and voltage, the Ivy Bridge is more efficient.

Also note that you can underclock a quad-core a lot more (which makes the CPU more efficient) and still get better multi-threaded performance.If efficient multi-threaded performance is what you're after, an Ivy Bridge quad-core is generally going to be your best bet if your budget doesn't allow for more expensive CPUs. But generally != always... what sort of number-crunching do you want to do exactly?

For a general-purpose computer, a cheap Sandy Bridge like the G530 would be good enough and efficient.

Yes, if anything it should work better than with previous generations.But it's sill not supported and I bet the tests you're talking about don't take stability into account.

I thought to have already grant the right credits to your propositions in my incipit.

I'm not quite interested into, my point was just that it's doable, a sort of reaction to the (initial) lack of (real) suggestings: but in case he is who should do it (including to take into account the stability issue).

the machine will mainly be used as a web-server (small traffic), mail, video streamer and NAS. At this moment it is all served by a single core athlon which is ok, but I'd like to keep machine responsive to the outside world when I'm copying files, for instance. Therefore I certainly need at least dual core CPU.

The underclocking with software tools is not an option, I'm on BSD. Therefore I'm limited to what BIOS provides.

I have been going through manual of ASUS board, and it seems to support CPU voltage adjustment, by setting an offset, which can be negative value as well. Isn't it the same as doing it through SW on Windows OS?

the machine will mainly be used as a web-server (small traffic), mail, video streamer and NAS. ... I'd like to keep machine responsive to the outside world when I'm copying files, for instance.

That's an I/O issue, not a CPU issue.You'd probably be fine with the cheapest Sandy Bridge or even with something slower. I probably would use something even slower.

For that usage, undervolting would be a waste of time in my opinion. It's mostly useful if you put a serious load on the computer most of the time. A small server is going to sit idle all the time unless you want to run a distributed computing app on it or something.

alexx wrote:

Isn't it the same as doing it through SW on Windows OS?

I don't know if it's even possible to do it in Windows. That Asus board should do what you want. But Asus boards typically waste power, more than you'll save if your server is idle most of the time.

thanks. That's why I've been seriously considering 2120T version, which is cheaper, not so speedy, but economical under load.

There was a post here claiming that DH77EB with 3770K was at 24W idle. It's quite difficult to believe. Since I need to do quite some hardware rotation in my house, I was considering to put E8200 to this task on DG45FC board. But the latter will probably idle at 40W. Not sure if 16W difference will ever pay for investment in a new setup though...

of course it's not entirely that simple. For web-servers, the bottleneck is often in IO, provided one has sufficient amount of RAM and good CPU. Ways to solve it, is by caching web-content in RAM, using SSDs, properly partitioning, etc...

At anyway, for a small server, the 3550 looks clearly a way overkill, while the T SKU looks useless. IMO.

If you need more threads/cores, what about AMD? The Trinity (Piledriver) A10 mobile chips would look promising (even if currently I don't think the relevant desktop power efficiency can be enough closer to Sandy Bridge one), providing the costs are somewhat lowered by AMD (a G530 with an H61 combo would come for under 100 euros in Italy).

as I mentioned previously, I have been quite happy with my existing setup with AMD and gigabyte MB, but I did get disappointed when I started looking for a CPU upgrade. First it turned out that I had very first revision of the board, for which gigabyte does not provide BIOS updates anymore and so the latest C3 stepping processors are not supported. Finding previous generation C2 is close to impossible. Next to that, most of the higher performance AMD CPUs are quite power hungry; the 'e' series of AMD athlons is also impossible to buy it seems...

Based on the above, and the fact that intel is really making amazing steps towards smaller and more efficient chips, I thought this time is better to go with intel. I think 1155 socket will be around for some time, and later finding second hand quad core should not be an issue, if I'll need more power. I hope I can build the machine that will serve me for 3-4 years without major upgrades.

I'm not sure what you're asking, Luca.Which are the (hypothetical) ways to prevent the copying of files from making a server unresponsive form a power/noise perspective? Is that it?

Copying a file is of course not an operation limited by the CPU's speed or by the number of cores.Responsiveness while you copy a large file is a software issue. You can't solve the problem completely by throwing hardware at the problem but you can simply solve it with reasonable I/O scheduling and/or prioritizing. What your software needs to do basically is to copy a bit of the file then pause the copying for long enough to allow any requests to be handled.A good server OS will do something like this by default but it can help if you tell the OS that it may delay the completion of the copying operation to respond to unrelated requests.

the machine will mainly be used as a web-server (small traffic), mail, video streamer and NAS. ... I'd like to keep machine responsive to the outside world when I'm copying files, for instance.

That's an I/O issue, not a CPU issue.

any hardware upgrade could just lower the average power consumption (less money to run, but at the build cost), if any, but there wouldn't be any I/O "performance" upgrade by an hypothetical replacement rig (leaving aside any improvement due to the new SATA III interface when paired with SSDs). Or, which is the same, even now there should not be any I/O "performance" issue to address (so that a new dedicated streaming NAS would probably serve better?).

You might want upgrades for other stuff even if you don't need an upgrade to copy files. Copying files is not the most exacting operation...I/O-wise, the H77 or even the H61 would certainly be an improvement. The CPU would presumably be faster and the system would also consume less power as you note, especially at load. But perhaps the OP simply wants more RAM. I don't know.

But you're right: I would tend to recommend against pointless upgrades. If the existing system can be made to perform OK for the time being, you'll be able to get a better upgrade next year.

It undervolts nicely, and it has an unlocked multiplier. Oh yes, AFAIK it's a C2 (I've got two in the last two years, and both can unlock the fourth core). It's not a brand new rig, not such an efficient solution, but it's relatively cheap (about a Pentium G620 alone).

I'm actually trying to postpone upgrades as long as I can; the example with file copying was just one thing that came to mind, not a real issue. Being in software for 15+ years, I'm sure I can address that. The upgrade is driven by many factors, first being that my backup PC is running out of steam (Pentium II 768MB RAM with 4 SATA disks on promise cards, adding more is not an option). So the plan is to move current server to the backup, possibly current desktop to the server, etc. you get the idea. In my view by doing such HW rotation I save money and improve on electricity bill.

it seems my setup is going to be: intel DH77EB, Celeron G540, 8GB RAM, two notebook drives. I'm considering picoPSU to power this machine, but I'm in doubt if I should go for 90W pico + 90W AC/DC brick or more powerful, i.e. 120W?

it seems my setup is going to be: intel DH77EB, Celeron G540, 8GB RAM, two notebook drives. I'm considering picoPSU to power this machine, but I'm in doubt if I should go for 90W pico + 90W AC/DC brick or more powerful, i.e. 120W?

Pick the best brick you will be able to find (check JonnyGuru for a review about bricks), but you won't go over 60-70W at full load, IMHO.

I doubt you'll come close to 50W DC without power-hungry peripherals (USB for instance). Even 40W is a stretch.

IMO, you should pick your pico and brick not based on your current components but based on what you might want to upgrade to down the road. Not only the CPU but also the drives, add-on cards and so on.Because if you're not planning serious upgrades down the road, you might as well pick a cheaper board or even something like the DH61AG which includes the equivalent of a pico and which is probably more reliable and more efficient as well.

possible short-term upgrade could be additional network card.long-term: if the server will get too busy, eventually I might need to go for ivy-bridge i5-3550 (77W TDP). Would the 90W be sufficient then? I guess not...

w.r.t. DH61AG: interesting indeed, but I guess more mainstream board is more suitable for my build.

The TDP rating is significantly higher than the actual power consumption (at least as long as you don't run stuff like Furmark on the IGP) so 90W could easily be sufficient for a quad-core (depending on the details).

If the CPU and a network card are the only upgrades you're planning, I'm not sure you need one of the new boards for this.

Talking about more mainstream gear: what about using a server board for a server? I've used desktop board for small servers as well but ideally...

Last edited by HFat on Sat Jun 09, 2012 6:44 am, edited 1 time in total.

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